Digitally controlled electrohydraulic (EH) closed-center valves and load sensing hydraulic pump systems have been quickly replacing the older generation of hydro-mechanically controlled (pilot actuated, mechanically controlled) open-center valves and fixed displacement pump systems in mobile equipment applications such as earth moving and construction equipment (i.e. wheel loaders, excavators, ...

The paper presents a laboratory model of the 3D tower crane. The arm of the crane is approx 1.2m long and the model is approx. 1.5m heigh. The crane is equipped with three DC motors that control: the rotary movement of the tower, the movement of the trolley and up and down movement of the load. The model is equipped with an unique unit for measuring an angle position of the load. The paper cont...

The natural sway of crane payloads is detrimental to safe and efficient operation. Under certain conditions, the problem is complicated when the payloads create a double-pendulum effect. Most crane control research to date has focused on single-mode dynamics. For example, several researchers have shown that signal-mode oscillations can be greatly reduced by properly shaping the inputs to the cr...

The NIST Construction Metrology and Automation Group, in cooperation with the NIST Intelligent Systems Division, is researching robotic structural steel placement as part of a project to develop an Automated Steel Construction Testbed. The initial phase of this project centers on tracking a six degree-of-freedom robotic crane with a laser-based site measurement system to provide position feedba...

Lateral root formation is an important developmental component of root systems in vascular plants. Several regulatory genes for lateral root formation have been identified from recent studies mainly using Arabidopsis thaliana. In this study, we isolated two dominant mutant alleles, crane-1 and crane-2, which are defective in lateral root formation in Arabidopsis. The crane mutants have dramatic...

The process of surveying crane runways has been continually refined due to the competitive situation, modern surveying instruments, additional sensors, accessories and evaluation procedures. Guidelines, such as the International Organization for Standardization (ISO) 12488-1, define target values that must be determined by survey. For a crane runway these are for example the span, the position ...

Sway reduction is very vital in a nonlinear oscillatory system such as a gantry crane. In this paper, a new design is proposed for active sway control of a gantry crane using an electrical ducted fan. The thrust force developed by the motor is used to cancel out payload oscillation. A dynamic model of the crane with a ducted fan is derived and simulated using Matlab. Performance of the proposed...

To the 36 meters crane girder with trapezoidal variable cross-section in a steel plant, finite element model is established reasonably according its actual size. The calculation of crane girder structure was introduced by using the finite element analysis software ANSYS. The local stress state of the cross-section is investigated and the stress concentration position of variable cross-section i...